The invention relates generally to thermal inspection systems and methods and more specifically, to non-destructive thermal inspection of cooled parts.
Hot gas path components, such as turbine airfoils, employ advanced cooling techniques, such as film cooling, as well as advanced coatings, such as thermal barrier coatings (TBCs), in order to withstand their extremely high operating temperatures. Film cooled components are typically inspected manually using pin checks, which involve the use of undersized pin gauges, and/or by water flow visualization, which involves flowing water through the component and having an operator visually verify that the water is flowing from each cooling hole. These manual approaches are qualitative and subject to operator interpretation.
Infrared (IR) inspection techniques have the potential to perform quantitative, objective inspection of film cooled components. However, IR inspection systems and current airflow check systems typically have conflicting requirements, thereby necessitating the use of separate systems, at considerable expense. Further, existing IR inspection systems are often limited to the inspection of uncoated parts.
It would therefore be desirable to develop a combined IR inspection and airflow check system. It would further be desirable for the inspection system to be capable of inspecting coated parts, for example of inspecting hot gas path components with TBCs.